/**
 * @since 2007-9-20
 * @author yijinhua
 */

function getDomDocumentPrefix() {
	if (getDomDocumentPrefix.prefix)
		return getDomDocumentPrefix.prefix;
	
	var prefixes = ["MSXML2", "Microsoft", "MSXML", "MSXML3"];
	var o;
	for (var i = 0; i < prefixes.length; i++) {
		try {
	
			o = new ActiveXObject(prefixes[i] + ".DomDocument");
			return getDomDocumentPrefix.prefix = prefixes[i];
		}
		catch (ex) {};
	}
	
	throw new Error("Could not find an installed XML parser");
}

function getXmlHttpPrefix() {
	if (getXmlHttpPrefix.prefix)
		return getXmlHttpPrefix.prefix;
	
	var prefixes = ["MSXML2", "Microsoft", "MSXML", "MSXML3"];
	var o;
	for (var i = 0; i < prefixes.length; i++) {
		try {
	
			o = new ActiveXObject(prefixes[i] + ".XmlHttp");
			return getXmlHttpPrefix.prefix = prefixes[i];
		}
		catch (ex) {};
	}
	
	throw new Error("Could not find an installed XML parser");
}





function XmlHttp() {}

XmlHttp.create = function () {
	try {
		if (window.XMLHttpRequest) {
			var req = new XMLHttpRequest();
			

			if (req.readyState == null) {
				req.readyState = 1;
				req.addEventListener("load", function () {
					req.readyState = 4;
					if (typeof req.onreadystatechange == "function")
						req.onreadystatechange();
				}, false);
			}
			
			return req;
		}
		if (window.ActiveXObject) {
			return new ActiveXObject(getXmlHttpPrefix() + ".XmlHttp");
		}
	}
	catch (ex) {}

	throw new Error("Your browser does not support XmlHttp objects");
};


function XmlDocument() {}

XmlDocument.create = function () {
	try {

		if (document.implementation && document.implementation.createDocument) {
			var doc = document.implementation.createDocument("", "", null);
			
	
			if (doc.readyState == null) {
				doc.readyState = 1;
				doc.addEventListener("load", function () {
					doc.readyState = 4;
					if (typeof doc.onreadystatechange == "function")
						doc.onreadystatechange();
				}, false);
			}
			
			return doc;
		}
		if (window.ActiveXObject)
			return new ActiveXObject(getDomDocumentPrefix() + ".DomDocument");
	}
	catch (ex) {}
	throw new Error("Your browser does not support XmlDocument objects");
};


if (window.DOMParser &&
	window.XMLSerializer &&
	window.Node && Node.prototype && Node.prototype.__defineGetter__) {

 
	Document.prototype.loadXML = function (s) {
		

		var doc2 = (new DOMParser()).parseFromString(s, "text/xml");
		

		while (this.hasChildNodes())
			this.removeChild(this.lastChild);
			

		for (var i = 0; i < doc2.childNodes.length; i++) {
			this.appendChild(this.importNode(doc2.childNodes[i], true));
		}
	};
	

	Document.prototype.__defineGetter__("xml", function () {
		return (new XMLSerializer()).serializeToString(this);
	});
}